Fuel metering valve



t i l l United States Patent() 3,103,543 FUEL METERING VALVE Joseph G. Zubaty, Leonard F. Stewart, and .lohn L.

Grabiel, Flint, Mich., assignors to General Motors Corporation,'Detroit, Mich., a corporation of Delaware Filed Aug. 30, 1966), Ser. No. 52,905 Claims. (Cl. 261--22 rDhe present invention relates to a -throttle controlled fuel metering valve for `a charge forming device particularly adapted for use with sa fuel injection type fuel system. More specifically, the present invention relates to a throttle controlled fuel metering valve which is an improvement over a similar type valve as shown in copending application Serial No. 3,572, Zubaty, filed llanuary 20, 1960*. v

The present fuel metering waive 'is particularly adapted for use with light aircraft fuel systems in which it is desired to not `only meter fuel in accordance with throttle position but in which a supplementary control is also provided whereby the fuel-air ratio may be modified between rich and lean proportions Ito accommodate the system to changes in power demand such as occur between take-off and cruising conditions.

While throttle controlled fuel metering valves are generally old, the present invention represents a lunique design permitting accurate fuel metering by means of a relatively simple and economical valve arrangement.

In the present invention a common fuel bore is provided and slidably receives a pair of hollow sleeve members having orifices therein. A pair of tapered adjustably-fixed needle members are coaxially disposed 'within said common bore and coact with the orifices of the slidable sleeve members. The sleeve members are respectively adapted to be controlled in their sliding movement 'by the throttle valve 'and by la rich-lean control member.kv rlihus, with the slidable sleevesy being arranged in series, ow between the throttle controlled sleeve and its needle valve will determine the rate of fuel liow in accordance with throttle position whereas this flow may be further restricted in flowing through the rich-lean lever controlled sleeve prior to its being distributed to individual cylinder injector nozzles. By thus providing separate regulatable sleeve members which coact with independent needle valve members, a more accurate type of fuel control is possible.

The details as well ias other objects and advantages. of the present invention will be apparent from a perusal of the detailed description which follows.

vIn the drawings:

FIGURE l is a diagrammatic representation of a fuel system embodying the subject valve; land FIGURE 2 is a plan view of the metering Ivalve of FIGURE l.

The drawings show the subject fuel metering -valve in detail. Referring to FIGURE l, the metering valve is shown within a diagnammatically represented 'fuel systern basically of the type shown in the aforenoted copending application.

The fuel system basically includes an air intake casing 1% including an air induction passage 12 having la throttle valve 14 mounted on a shaft lo for rotation within the induction passage. Induction passage 12` is adapted to supply 4air to the intake manifold of Ian engine, not shown. A throttle controlled fuel metering valve is indicated generally at 18 and is supplied with fuel from an engine speed responsive pump 2li through a conduit 22. Pump Ztl is in turn supplied from reservoir 24 through any suitable transfer pump 26.

Metered fuel is supplied from valve i8 through con- ICC duits 2S to individual fuel injectors 30. The basic fuel vsystem is described in the aforenoted copending application and for present purposes it will suffice to note that fuel is supplied to metering valve 18 by pump Ztl under presure proportional fto engine speed with the basic quantity of fuel supplied to injectors y30 being modified through the valve in accordance with throttle position.

Referring now more particularly to metering valve 18, a casing member 32 is adapted to be suitably mounted on air intake `casing |10 proximate throttle valve 14. Casing 32 includes a longitudinally extending open-ended cylindrical passage or bore 34 within which hollow sleeves 36 and 38 are slidably supported. The outer ends of bore 34 are counterbored to threadably receive plug or cap members 4l? `and 42. Caps 4t) and 42, vin turn, respectively threadably support tapered needle elements 44 and 46 which are coaxially aligned with bore 34 fand extend axially therewithin. For reasons which will be better understood subsequently, each of the tapered elements 44 and 46 may be -aXially adjusted relative to its supporting cap to vary its axial penetration within bore 34.

Needle element 44 includes a tapered portion 48 intermediate its ends which is adapted to coact with an orifice Sii formed in the outer end lof sleeve 36 to provide a variable size orifice.

Metering valve casing 32 includes ra conduit 52 communicating at one end with pump supply conduit 22. and opens iat yits other end within a chamber `54 intermediate end cap 40 and sleeve 36. Thus with the throttle closed, the parts will be in the` position shown in FIGURE Il in which sleeve orifice Stil coacts with tapered portion 48 of needle element 44 blo-cking the flow of fuel through sleeve 36. As will subsequently be considered in greater detail, an idle fuel bypass is provided to permit engine idling under these conditions,

Throttle shaft 16 extends axially beyond air intake casing 1li land projects within metering valve casing 32 land supports a gear member 56 `on the outer end thereof. Gear 55 is disposed in an enlarged portion 58 of casing 32 and meshes with a rack portion 60 formed on sleeve 36. The other end of throttle shaft 16 includes a lever 62. adapted to be suitably articulated to :an operator controlled mechanism to control the angular position of the throttle valve in any well known manner.

As throttle valve 14 is moved to a progressively more open position, gear 56 will be rotated in a counterclockwise direction, as viewed in FIGURE l, moving sleeve 36 axially inwardly whereby sleeve orifice 50 will be positioned adjacent progressively more reduced portions of the tapered portion 48 of element 44- thereby increasing the quantity of fuel flowing from chamber 54 through sleeve 36.

One end of casing 32 is enlarged to provide a fuel distributor y64 having a plurality of outlets 66 adapted to communicate with injector conduits 28. The inner ends of outlets 66 communicate with an outlet chamber 68 defined by end cap 42 and slidable sleeve 38. Here again, orifice end of sleeve 36 coacts with tapered portion '72. `of element 46 to provide a variable orijce in series with variable orifice 48-50 to modify the quantity of metered fuel supplied to injectors 30 in accordance with certain engine operating conditions.

In this instance, variable orifice 7ll-72 is regulated by ,a rich-lean control lever 74 fixed to a shaft `'76 which is rotatably mounted within casing 32. A gear member 78 is fixed to shaft 7o and is supported within portion 8o of casing 32. Gear '78` meshes with la rack portion 82 formed on sleeve 38. During high power demand conditions such ias occurs during take-off, it is necessary to have a richer-than-norinal fuel-,air ratio whereas during normal operating conditions a relatively lean fuel-air ratio will provide satisfactory engine operation. Accordingly, during power conditions lever 74 is rotated tto move sleeve 38 naxially inwardly relative to casing 32 to provide the maximum yopening between the sleeve `and tapered element 46 to thereby insure an enrichment of the fuelair ratio. Lever 74 and Sleeve 38 are shown in the fullrich position. During normal operation, lever 74 and sleeve 38 are moved to a 'lean position thereby reducing the fuel-air ratio to insure economical operation of the engine.

To prevent the system from draining into the engine cylinders when the engine is Shut off, means is provided for cutting `off the flow `of fuel through fuel metering valve 18. End cap 4Z includes la boss portion '84 extending .axially within fuel `outlet chamber 68 and supports an `O-ring 86 thereon. Sleeve 38 includes a chamfered or tapered portion 88 which, When the rich-lean lever 74 is moved tot a fuel cut-off position will coact with =O ring 86 to seal any further flow to or from outlet chamber 68.

Thus in operation, lever 74 is set for either rich or lean flow after which the quantity of 4fuel dow through the metering valve is ydetermined by the position of throttle valve 14.

It is apparent that by making the tapered e-lements 44 and 46 adjustable Within their respective end caps 40 and 42., fuel ow through metering Valve 18 may be tailored very precisely to the operating characteristics of the particu-lar engine on which the system is to be incorporated, lFurther, by providing individual tapered elements 44 and 46 as Well as individual slidable sleeves 36 and 38, lean-rich fuel flow control may be tailored independently of a simil-ar type independent adjustment of flow through the throttle control-led portion of the metering |valve.

An adjustable stop gli is mounted on casing 16 and is adapted Ito be abuttingly engaged by a lever 92 fixed to throttle shaft 16. In this Way idle air ilow around the closed 'throttle valve may be adjusted. At the same time, -idle fuel flow through metering valve 13 may be regulated by providing an iadjustable needle valve 94 which controls a fuel bypass passage 96 communicating with supply conduit 52 whereby :a limited amount of fuel can bypass sleeve 36 and element 44 to maintain the engine in an idling condition even though fuel flow through oriiice 50 is otherwise prevented by the position of sleeve 36, supra.

We claim:

l. A fuel metering mechanism for an internal combustion engine of the type including an intake passage for supplying air to the cylinders of the engine, a throttle valve rotatably supported Within said passage for controlling air flow therethrough, pump means for supplying fuel under pressure proportional to engine speed, and a plu-rality lof nozzles adapted to supply fuel to the engine cylinders, said fuel metering mechanism comprising a casing, a first sleeve member siidably disposed Wit-hin said leasing rand having an orifice centrally formed therein, a first metering rod supported within said casing and projecting through said sleeve member orifice, means lassociatcd with said orifice adapted to connect the fuel outlet of the pump of such engine thereto, a second sleeve member Slidably ldisposed in said casing intermediate said first sleeve member and outlets in said casing adapted to be connected to the nozzles of Such engine, said second sleeve member including a second orifice, a second metering rod mounted on said casing and adapted to coact with the orifice of said second sleeve member to control the iiow of fuel through said second orifice in accordance with the position of said second sleeve member relative to said second rod, land means for adjusting the axial positions of said first and second sleeve members relative to said metering rods, said ori-lices being arranged in series whereby the fuel ow through said metering mechanism may be controlled by adjusting said sleeve members relative to their associated metering rods.

2. A fuel metering system for an internal combustion engine las set forth in claim l in which the means for axially adjusting said sleeve members includes a lever and gear device connected to said first sleeve member and adapted to be connected to the throttle valve of such engine.

y3. A fuel metering system for an internal combustion engine as set forth in claim l which further includes a fuel enrichment member and in which the means for 'axially adjusting said sleeve members comprises ra first 'lever and gear device connected to said first sleeve member rand adapted to be connected to the throttle Ivalve of such engine and a second lever and gear device connected rto said Second sleeve member land adapted to be conneoted to the fuel enrichment member of such engine.

4. A fuel meteringsystem for an internal combustion engine as Set forth in claim 1 in which each -of said metering rods is adjustably mounted in Said casing whereby the basic axial relationship bet-Ween the :associated metering red and sleeve orilice may be varied.

5. A fuel metering system for an internal combustion engine as Set forth in claim 1 in which each metering ro'd is adjustably mounted in an end cap member threaded within said casing, the second metering rod supporting end cap including a boss extending axially Within said casing, said second sleeve member being movable into engagement with said boss to block fuel ilow to the outlets in said casing adapted to be connected to the nozzles of such engine.

References Cited in the tile of this patent UNrrED STATES PATENTS 

1. A FUEL METERING MECHANISM FOR AN INTERNAL COMBUSTION ENGINE OF THE TYPE INCLUDING AN INTAKE PASSAGE FOR SUPPLYING AIR TO THE CYLINDERS OF THE ENGINE, A THROTTLE VALVE ROTATABLY SUPPORTED WITHIN SAID PASSAGE FOR CONTROLLING AIR FLOW THERETHROUGH, PUMP MEANS FOR SUPPLYING FUEL UNDER PRESSURE PROPORTIONAL TO ENGINE SPEED, AND A PLURALITY OF NOZZLES ADAPTED TO SUPPLY FUEL TO THE ENGINE CYLINDERS, SAID FUEL METERING MECHANISM COMPRISING A CASING, A FIRST SLEEVE MEMBER SLIDABLY DISPOSED WITHIN SAID CASING AND HAVING AN ORIFICE CENTRALLY FORMED THEREIN, A FIRST METERING ROD SUPPORTED WITHIN SAID CASING AND PROJECTING THROUGH SAID SLEEVE MEMBER ORIFICE, MEANS ASSOCIATED WITH SAID ORIFICE ADAPTED TO CONNECT THE FUEL OUTLET OF THE PUMP OF SUCH ENGINE THERETO A SECOND SLEEVE MEMBER SLIDABLY DISPOSED IN SAID CASING INTERMEDIATE SAID FIRST SLEEVE MEMBER AND OUTLETS IN SAID CASING ADAPTED TO BE CONNECTED TO THE NOZZLES OF SUCH ENGINE, SAID SECOND SLEEVE MEMBER INCLUDING A SECOND ORIFICE, A SECOND METERING ROD MOUNTED ON SAID CASING AND ADAPTED TO COACT WITH THE ORIFICE OF SAID SECOND SLEEVE MEMBER TO CONTROL THE FLOW OF FUEL THROUGH SAID SECOND ORIFICE IN ACCORDANCE WITH THE POSITION OF SAID SECOND SLEEVE MEMBER RELATIVE TO SAID SECOND ROD, AND MEANS FO ADJUSTING THE AXIAL POSITIONS OF SAID FIRST AND SECOND SLEEVE MEMBERS RELATIVE TO SAID METERING RODS, SAID ORIFICE BEING ARRANGED IN SERIES WHEREBY THE FUEL FLOW THROUGH SAID METERING MECHANISM MAY BE CONTROLLED BY ADJUSTING SAID SLEEVE MEMBERS RELATIVE TO THEIR ASSOCIATED METERING RODS. 